PHILADELPHIA (CBS) — Police were investigating what they say may have been a drive by shooting early Thursday morning in South Philadelphia.

According to police, three men, two 28-year-olds and a 30-year-old, were shot shortly after 12:30 a.m. near 22nd and Reed streets in the city’s Point Breeze section.

Police recovered at least a dozen bullet shells in the street. Detectives were studying surveillance tapes for leads on possible suspects.

The 30-year-old male was being treated for a thigh wound at the Hospital of the University of Pennsylvania. The other two victims were listed in stable condition at Thomas Jefferson University Hospital.